Apparatus for automatically regulating temperature of steam-generating tubes



T. L. STURTEVANT. APPARATUS FOR AUTOMATICALLY REGULATING TEMPERATURE OF STEAM GENERATING TUBES. v

Patented May 28, 1889.

(No Model.)

UNITED STATES PATENT OFFICE.

THOMAS L. STURTEVANT, OF FRAMINGHAM, MASSACHUSETTS.

APPARATUS FOR AUTOMATICALLY REGULATING TEMPERATURE OF STEAM-GENERATING TUBES.

SPECIFICATION forming part of Letters Patent No. 403,972, dated May 28, 1889.

Application fil February 11, 1889. Serial No. 299,449. (No model.)

To all whom it may concern:

Be it known that I, THOMAS L. STURTEVANT, a citizen of the United States, residing at Framingham, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Apparatus for Automatically Regulating Temperature of SteanrGenerating Tubes; and I do hereby declare the following to be a full, clear, and exact description of the invention, such'as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

This invention relates to steam-generators, particularly to that class in which a forced circulation is employed, the water, in lieu of remaining in the generator, which generally serves as a reservoir as well as a steam-generating chamber, being compelled to pass continuously into and through the tubes composing said generator, such continuous sup- 2 5 ply being furnished by some suitable liquidforcing apparatus, while the water so introduced is gradually raised in temperature during its passage therethrough and finally converted into vapor or steam and discharged under pressure to any'desired source.

In the above class of steam-generators the heating agency generally consists in some variety of burner in which liquid fuel is to be used; hence with the intense heat derived therefrom itbecomes necessary that the watersupply should be forced through the generator in such quantities as will prevent excessive heating of the tubes, which might be burned, or, on the other hand, overfilled with water by a powerful pump. IVater is then mingled with the steam. The conditions are thus fluctuating between one and the other extreme and dependent upon the amount of steam being used; but the serious and constant danger is the overheating of the tubes.

To overcome these difficulties is the object of my invention. To this end I have adapted a system or method of self-regulating steamgenerators having a forced circulation, and which consists in controlling the supply of the water continuously passing through the generating-tubes to regulate the heat of said tubes, this being accomplished by means of the temperature of the steam or water within such tubes, it being understood that a high temperature of the steam does not necessarily indicate a high pressure.

Furthermore, my invention consists in Various instrumentalities by which said system is practically accomplished. These instrumentalities or their equivalents consist, primarily, in a thermostat to be influenced by the temperature of the steam within a tube or tubes of the steam-generator operated under my system, electro-magnetic mechanism controlled by the thermostat and operating to regulate the supply of steam to the fluidforeing apparatus, and a heating agency, all of which will be more fully hereinafter explained. Thus the power of the steam-generator is maintained at a maximum, for the heat is kept at its full intensity, while sufficient water is injected to regulate the temperature of the tubes and dependent upon varying circumstances.

A further prominent feature in my invention is the combination, with the generator and the liquid-forcing and heat-regulating apparatus, of a valve (hereinafter indicated by the letter L) which has for its object the continuous operation ofthe generator and all its parts at all times; Thus when the engine stops some escape must be provided for the steam. This valve must be placed in some position where the steam and water will circulate through the whole system, or unless the lamp is turned down instantly or the fire checked or removed the tubes will be overheated. This valve, then, at the end of the system for creating steam at a point just after it emerges therefrom and before it reaches the engine or pump is required and is of vital importance to the successful operation of generators of this class.

The drawings represent, in Figure 1, a sectional elevation of a steam-generator of the class above premised in which my improvements are introduced. Fig. 2 is an enlarged detail View of the thermostat. Fig. 3 is an enlarged view of the connection between the lever H and valve-stem.

In said drawings I have represented one and are contiguous therebetween, thus serving as supports or braces to the tube-sections, which can consequently be made of thin metal.

To carry out my invention, and in order to regulate the heat of the tubes automatically by the temperature of the steam therein at a g certain predetermined point, and, further,-to avoid reducing the intensity of the heating;' agency, and therebyproportionately dimin-' ishing the efficiency of the generator, I have arranged the several instrumentalities which serve to accomplish my invention, combined in one way for purposes of illustration.

At B is represented a hydrocarbon-burner, of any suitable description and located at one extremity of the generator, the opposite end of whichenters a chimney, by which the smoke and heat from the lamp are conveyed away.

At 0 is indicated a steam-pump, the water-impelling mechanism connecting with a fluid-supply pipe, 3, which leads, preferably, to the lamp end of the generator. The steamactuated portion of the pump is supplied by steam through the pipe 4, which is joined with the main steam-discharge pipe 5 from the generator. Located upon said pipe 5 is secured a thermostat, D, which is influenced directly by the heat of the steam passing through said discharge. This thermostat is preferably provided with a dial-plate, E, graduated with degrees for units of heat in temperature. Aflixed upon this plate are disposed insulated posts 6 6 6, corresponding to the degrees of heat upon the dial and adapted to receive removable keys or pins 7 7, changeable from post to post, in order to limit the variations in temperature, which is desired.

It is evident that the position or location of the thermostat is very important, for the following reasons: VVhen the engine stops, it

even fora moment, the steam must not only continue to circulate through the tubular gencrating system, but it must also circulate so as .to heat the thermostat, as usual; otherwise that instrument cannot regulate the water-supply, and therefore I have located it at From the latter wires 14 15 extend to the dialplate, their ends being furnished each with a key or pin, 7, changeable in said dial-plate, as occasion may require, to reduce or enlarge the limit of variation in temperature.

To control the supply of water which is continuously injected within the generator automatically, I permit the heat or temperature of the steam as it emerges from said generator to influence directly the thermostat, and have combined the following elements with those already previously described: Within and between the fields of the said electro magnetsI have pivoted a soft-iron bar or le- Ver, H, which is united at its free end with the extremity of a valve-rod spring-actuated at 16, which governs the valve L, located in the supply steam-pipe 4 to the pump. Thus, presuming the various component parts are arranged as shown, their manner of co-operating is as follows: The limit of steam temperature is, for illustration, assumed to be from 220 to 320 for a certain condition of lamp intensity. Accordingly the pins 7 7 are placed in the posts which correspond to such variations of temperature. Between such limits the valve L is supposed to be in a nor- .mal position and so held by the springs 16;

but if for any cause whatsoever the temperature reaches the outside limit (320) themovement of the pointer G over the post 6 causes it to wipe the latter, when the .circuith-ithert-o open is now closed,the magnet 13 is rendered active, the lever H is magnetically attracted, and the valve L is shifted to partially increase the steam-supply. As a consequent result the speed of the pump is accelerated and a larger supply of water is injected within the generator within a given unit of time; but since'the intensity of the heating agency is supposed to be constant, or practically so, the temperature of the steam is accordingly reduced. On the other hand, in case the temperature should fall below the desired point areverseaction occurs. The electro-magnet 12 then becomes active. When the hand G has reached the post corresponding to 220 of temperature the Valve L is operated to reduce in part the steam-supplyto the pump. The amount of water injected is lessened, while as a consequence the temperature of the steam as it emerges from the generator will be .increased. Thus it is evident that by means of the above-described mechanism or its-equivalent my improvements can be readily carried out in steamgenerators provided with a forced circulation.

Ordinarily the service of pumps in connection with boilers is simply to regulate the depth of water therein. In my arrangement, however, the pump is intended to control the temperature of the tubes, as indicated by the temperature of the steam.

What I desire to claim is-- 1. In steam-generators having a forced circulation, the combination, with a generator of such class and a suitable heating agency,

IIO

of water-forcing apparatus, a thermostat controlled by the steam temperature within said generator, and electro -magnetic apparatus connected with and operated by said thermostat to regulate the steam delivered to the fluidforcing apparatus, whereby the supply of water delivered serves to control the temperature of the tubes composing the generator, substantially as herein set forth.

In steam-generators provided with a forced circulation, the combination, with a generator of such class, a suitable heating agency, the liquid-forcing apparatus, and the main steam-discharge 5, of a thermostat c011- nected with the latter interior-1y and proximate to the generator at a point between the generator and the source to be supplied, whereby the amount of liquid admitted within the generator is to be varied to suit the intensity of the heating agency, substantially as herein described.

3. In combination with steam generators having aforced circulation, a heating agency, liquid-forcin g apparatus, and steam-discharge pipe, a valve located in a branch of said discharge-pipe and being between the steamgenerating system and the source of supply to permit the continuous operation of the generator by alternately decreasing and increasing the supply of steam to the supplypump, all substantially as set forth.

4. The combination, with a steam-generator having a forced circulation, water-forcin apparatus, and the feed-valve 'L, of a thermostat and the electro-magnetic apparatus actuated thereby and electrically united with said thermostat and with said valve L to control the movements of the pump and regulate the temperature of the steam-producing tubes, substantially as specified.

5. The steam generator of the class herein described, its heating agency B, and the liquid-forcing apparatus 0, combined with the steam-valve L, the thermometer G, regulated by the steam temperature within the genera.- tor, the lever-rod H, and means-namely, the electromagnetic apparatus uniting said lever and the thermometerwhereby to control the forcing apparatus, as and for purposes described.

6. In combination with a steam-generator, A, having a forced circulation, its heating agency B, the liquid-forcing apparatus 0, the valve L, and the thermostat D, which electrically controls the latter, the electro-m agnets 12 13, the lever H, actuated thereby, and the terminals 7 '7, changeable in the graduated dial-plate E to limit the temperature of the steam-producing tubes, as herein set forth and described.

In testimony whereof I affix my signature in presence of two witnesses.

THOMAS L. STURTEVANI.

\Vitn esses:

J. P. TAYLOR, R. L. DAINGERFIELD. 

